The vulcanization of diene elastomers by sulphur is widely used in the rubber industry, in particular in the tire industry. Use is made, to vulcanize diene elastomers, of a relatively complex vulcanization system comprising, in addition to sulphur, a primary vulcanization accelerator, such as sulphenamides comprising a benzothiazole ring system, and various secondary vulcanization accelerators or vulcanization activators, very particularly zinc derivatives, such as zinc oxide (ZnO), alone or used with fatty acids.
The sulphenamides comprising a benzothiazole ring system used as primary vulcanization accelerators are, for example, N-cyclohexyl-2-benzothiazolesulphenamide (abbreviated to “CBS”), N,N-dicyclohexyl-2-benzothiazolesulphenamide (abbreviated to “DCBS”), N-tert-butyl-2-benzothiazolesulphenamide (abbreviated to “TBBS”) and the mixtures of these compounds.
The rubber compositions have to exhibit satisfactory crosslinking while retaining an acceptable compromise between the different rheometric properties.